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Using the CC BY 4.0 License for Open Data

By Open Data Manual editors · Published 4 November 2026 · Editorial standard

The Creative Commons Attribution 4.0 International licence (CC BY 4.0) is one of the most widely used licences for open data. It allows any use, including commercial use and adaptation, on one condition: give appropriate credit. This guide explains what the licence means for datasets in particular, what users must do to comply, and how it compares with the alternatives. It expands on the manual's chapter Apply an Open License.

Why version 4.0 matters for data

Creative Commons released the 4.0 licences in November 2013. For data publishers, the most important change concerned database rights. In the European Union and the United Kingdom, databases can be protected by a sui generis database right that is separate from copyright (see our guide to database rights). Earlier Creative Commons licences did not deal with this right consistently, which left uncertainty about whether a CC licence actually permitted extraction from a European database.

Section 4 of the CC BY 4.0 legal code addresses it directly. Where database rights apply, the licence grants the right to extract, reuse, reproduce and share all or a substantial portion of the database's contents. If you include a substantial portion in your own database, your database (though not its individual contents) is treated as adapted material, and the attribution conditions apply when you share it.

What users may do

• copy and redistribute the data in any medium or format;
• adapt it: clean it, merge it with other data, build services and visualisations on it;
• use it for any purpose, including commercial purposes.

The licence is not revocable by the licensor for users who comply. It also prevents anyone passing the data on from adding technical restrictions: section 2(a)(5)(B) bars applying effective technological measures if doing so restricts recipients' use of the licensed material.

What attribution must include

Section 3(a)(1) lists what a user must keep when sharing the material, if the licensor supplied it:

• the name of the creator and anyone else designated to receive credit;
• a copyright notice;
• a notice referring to the licence;
• a notice referring to the disclaimer of warranties;
• a URI or link to the material, where reasonably practicable.

The user must also say whether they modified the material, and indicate that it is licensed under CC BY 4.0 with the text of, or a link to, the licence. The licence allows this to be done "in any reasonable manner" suited to the medium. For a web application that uses a dataset, an "About the data" page or a footer credit is normally enough.

A common shorthand from Creative Commons' own guidance is TASL: Title, Author, Source, Licence. For example:

"Air quality readings 2025" by the City Environment Department, from data.example.gov, licensed under CC BY 4.0. Values aggregated to daily means.

Publishers make compliance much easier by supplying a ready-made attribution line on the dataset page and in the metadata.

The 30-day cure period

If a user breaks the conditions, for example by omitting attribution, their rights under the licence terminate. Section 6(b) provides that the rights are reinstated automatically if the violation is cured within 30 days of the user discovering it. This makes CC BY 4.0 more forgiving than older licences, under which a single lapse could end the licence permanently. The licensor can still seek remedies for the period of violation.

Attribution stacking

The main drawback of any attribution licence for data is that credits accumulate. A service combining 200 CC BY sources must credit each one. This is manageable with a credits page, but some publishers of reference data prefer CC0 for this reason. If you choose CC BY, make attribution as light as possible: a short, fixed credit line, and permission to give credit on a single credits page.

CC BY 4.0 compared with other licences

Licence	Attribution	Share-alike	Notes
CC0 1.0	No	No	Public domain dedication with fallback licence
CC BY 4.0	Yes	No	Covers database rights; 30-day cure
ODC-By 1.0	Yes	No	Open Data Commons equivalent written for databases
OGL v3.0 (UK)	Yes	No	For UK public sector information; states compatibility with CC BY 4.0 and ODC-By
CC BY-SA 4.0	Yes	Yes	Adaptations must use the same or a compatible licence
ODbL 1.0	Yes	Yes (for adapted databases)	See our ODbL guide

The Open Government Licence v3.0 used for UK public sector information states that its terms are compatible with CC BY 4.0 and the Open Data Commons Attribution License, so data under the OGL can be combined with CC BY data without conflict. All of the licences in the table appear on the Open Definition's list of conformant licences.

Avoid the NC and ND variants for open data

Creative Commons also offers licences with NonCommercial (NC) and NoDerivatives (ND) conditions. These are not open in the sense of the Open Definition, because they restrict who may use the data or what they may do with it. "Non-commercial" is also hard to interpret: it is not obvious whether a charity's fundraising site or a journalist's newspaper counts. If the goal is open data, use CC BY 4.0 or CC0.

Applying CC BY 4.0 to a dataset

1. Check that you hold the rights to everything in the dataset, and that it contains no personal data.
2. State the licence on the dataset page with a link to https://creativecommons.org/licenses/by/4.0/.
3. Give the exact attribution line you want users to copy.
4. Put the licence URL in the dataset metadata (dct:license in DCAT, license in DCAT-US and schema.org). Our guide to metadata standards shows where it goes.
5. Add a README with the licence and attribution line to every download.

Frequently asked questions

Can CC BY 4.0 be used for data and databases?

Yes. Unlike earlier versions, CC BY 4.0 explicitly licenses sui generis database rights in section 4, so it can be applied to databases as well as to text and images.

What attribution does CC BY 4.0 require?

If the licensor supplied them, you must keep the creator's name, a copyright notice, a reference to the licence, a reference to the warranty disclaimer and a link to the material, say whether you changed it, and indicate that it is under CC BY 4.0 with a link to the licence.

What happens if someone forgets to give attribution?

Their licence terminates, but it is automatically reinstated if they fix the problem within 30 days of discovering it. The licensor can also reinstate it expressly.

Is the UK Open Government Licence compatible with CC BY 4.0?

Yes. OGL v3.0 states that its terms are compatible with the Creative Commons Attribution License 4.0 and the Open Data Commons Attribution License.

Is CC BY 4.0 an open licence?

Yes. The Open Definition lists CC BY 4.0 among its recommended conformant licences.

More practical guides

• CSV vs JSON
• Metadata standards (DCAT)
• FAIR data principles
• The CC0 license
• Open Database License (ODbL)
• Database rights